1. Field of the Invention
The invention relates to a method and a device for generating noise in the vehicle interior and vehicle exterior of a motor vehicle.
2. Description of the Related Art
What is referred to as sound design for motor vehicles has, for many reasons, become a problem for the manufacturers of motor vehicles. On the one hand it is conceivable that an engine noise of a motor vehicle does not please a potential driver of the motor vehicle in terms of its form and the driver may like to change the noise that can be heard in the vehicle interior of the motor vehicle. For example, a user might like the engine sound that can be heard in the interior of the motor vehicle to be somewhat more sporty or somewhat quieter than has been provided hitherto. On the other hand, there are always wide ranging limiting values for external vehicle noise that have to be complied with. Thus, engine noise or other acoustic indications of driving states, such as speed or acceleration are manipulated in a targeted fashion in modern passenger cars.
In addition, motor vehicles are being developed increasingly with electric motor drives. These electric vehicles, of course, have extremely low noise emissions. However, this low noise emission has a disadvantageous safety aspect that should not be underestimated. These vehicles often are so quiet that they are not heard by a passersby or playing children when they approach. In particular, in the case of playing children noise from approaching vehicles is stored in the subconscious as an approaching danger. If a vehicle then approaches almost without any driving noise, the child will not perceive the vehicle or will perceive it too late. This can easily lead to accidents. On the other hand, motor vehicles have an entirely specific driving noise, exhaust noise and engine noise that is responsible, in a significant way, for the feeling of wellbeing of the driver and of the vehicle occupants. The feeling of wellbeing of the driver in turn makes quite a significant contribution to the vehicle being controlled in a safe way, and therefore contributes to general road safety. Accordingly, acoustic perception is an important safety factor.
The above-mentioned aspect also occurs in hybrid vehicles, and a driver perceives different noise in various driving modes that differ from the known, conventional driving noise, especially when the vehicle is driven exclusively via the electric motor.
DE 100 16 104 discloses a device for emitting noise to a passenger compartment of a motor vehicle. In this context, a resonance body is fit onto a signal source that is made available. The surface of the signal source forms one of the walls of the resonance body to which a line and further means for passing a noise into the passenger compartment are connected.
DE 10 2010 007 051 discloses a method and a device for generating sound in vehicles without an internal combustion engine. In this context, values for the parameters of the sound and frequency are selected as a function of the time, the position of the vehicle, the speed of the vehicle and the acceleration of the vehicle and are used to characterize the generation of sound. Differentiated irradiation toward the inside and toward the outside takes place during the generation of sound.
EP 1 936 605 discloses a sound transmitting device for transmitting sound of an operational noise of a motor vehicle, namely an air filter noise, into the vehicle interior of the motor vehicle. The presented sound transmitting device comprises a transmitting line for transmitting the noise from the noise source into the vehicle interior. The transmitting line is formed at least partially by at least one component that already is present independent of the sound transmission on the motor vehicle.
U.S. Pat. No. 5,635,903 describes a noise generator for electrical vehicles. The noise generator generates a noise that is emitted into the vehicle interior of the motor vehicle. Amplifiers and loudspeaker units also are provided to permit the emission.
WO 03/100764 describes a device for carrying out noise control in a motor vehicle. The device has a hollow body that is divided into at least two spaces by a sound transmitting device. One space is connected via an input line to a gaseous part of an internal combustion engine of the vehicle, and the other space is coupled acoustically by an output line to an interior of the vehicle and/or to the space surrounding the vehicle. The output line also has at least one branch from which at least two branch lines run at different locations in the vehicle interior and/or the space surrounding the vehicle.
An object of the invention to create a suitable acoustic profile for an electric vehicle or a hybrid vehicle that takes into account different noise sources and supplies an authentic vehicle sound that can be used independently of a driving mode. In this context, the external noise of a vehicle is also of particular importance alongside the frequently considered internal noise. The invention simply and efficiently solves the problems of external noise and internal noise as well as simply and efficiently manipulating the noise in the interior of a motor vehicle and simulating an engine noise that is not present when a hybrid vehicle is driven electrically.